Obtain reliabel data and trustworthy kinetic parameters for the uptake of cell nutrients and non-metabolizable analogues of these nutrients for a number of different normal cell lines (chicken and mouse embryo cells), and for the malignant cells derived from these, following viral or chemically induced trasformation, the objective of these studies being to determine whether the process of carcinogenesis leads to the formation of new classes of membrane transport components of merely to the increased production of existing components. Study the time course of emergence of the new transport kinetics following cell transformation to the malignant state. Evaluate the influence of cell density on transport properties to determine the contribution cell-cell interactions. Identify competitive and irreversible inhibitors of the malignant-specific transport system in an effort to design site-directed irreversible inhibitors. Perform studies with membrane vesicles prepared from the above cell lines.